This invention relates generally to a trigger actuated pump sprayer, and more particularly to a combined liquid pick up end container vent arrangement permitting pump operation without leakage in any attitude of the pump sprayer. The container vent is unvalved and admits air into the container as required to replace the dispensed liquid to prevent hydraulic lock end container collapse in the presence of a sub-atmospheric pressure condition within the container. Likewise, when spraying a gas/vapor producing liquid product such as a chemical cleaner or the like producing a superatmospheric pressure, the container vent releases such super-atmospheric pressure from the container to thereby maintain an equilibrium pressure.
Known trigger actuated pump sprayers, exemplified by U.S. Pat. Nos. 4,747,523, 5,344,053 and 4,072,252, here wired container vent means operable during pumping for admitting air into the container through a container vent port to avoid a sub-atmospheric pressure condition in the container during dispensing. However, during operation of the trigger sprayer while inverted or tilted from upright, there is a tendency of product to leak out through the vent without the provision of additional valving.
Moreover, when any of these known trigger sprayers is mounted on a container of gas/vapor producing liquid product such as a cleaning chemical capable of generating an elevated pressure in the container, such internal pressure tends to exert undue pressure against the trigger lever via the vent port end vent passage which interferes with pump operation. And, the superatmospheric pressure condition in the container tends to expand the container sidewalls producing an undesirable condition.
U.S. Pat. Nos. 4,722,463 and 4,186,882 disclose the use of a float at the end of a vent tube for maintaining the air inlet always at a position above the surface of the liquid regardless of the orientation of the container.
Other U.S. Pat. Nos., such as 5,195,664, 4,830,235, 4,273,272, 3,580,430, and others, each provide for a weighted free end of a flexible dip tube to maintain the liquid inlet always in communication with the liquid irrespective of the attitude of the container when pumping.